Substituted pyrazolylpyrazole derivative and use of same as herbicide

ABSTRACT

Provided is a compound capable of effectively control worst weeds of higher leaf stages that present practical problems. A specific pyrazolylpyrazole derivative of formula (1) is disclosed that is able to solve the above-mentioned problems.

TECHNICAL FIELD

The present invention relates to a substituted pyrazolylpyrazolederivative and the use of that compound as an herbicide.

BACKGROUND ART

Numerous herbicides have recently come to be used in the cultivation ofagricultural crops, and have contributed to reduced labor for farmersand improved productivity of agricultural crops. Numerous herbicides arealso used practically in the cultivation of field and paddy rice.

However, there is considerable diversity in the species of weeds, thegermination and growth periods of each species of weed are not uniform,and the growth of perennial weeds extends over a long period of time.Consequently, it is extremely difficult to control all weeds with asingle spraying of herbicide.

Early to mid-term one-shot herbicides have been shown to be effectivefor paddy rice by treating during the second to third leaf stage ofpaddy weeds (generic term for Echinochloa oryzicola, Echinochloacrus-galli var. crus-galli, Echinochloa crus-galli var. formosensis,Echinochloa crus-galli var. praticola and Echinochloa crus-galli var.caudata), and major weeds can be controlled by a single treatment (seeNon-Patent Document 1). However, it is extremely difficult to controlpaddy weeds that have grown to the 3.5 leaf stage or more with early tomid-term one-shot herbicides currently in practical use, and the controlof paddy weeds in the third leaf stage and control of paddy weeds in the3.5 leaf stage are technically completely different.

Moreover, maintaining herbicidal effects (residual activities) over along period of time is important in terms of reducing spraying ofagricultural chemicals, saving on labor and curtailing costs, and isconsidered to be an essential area of performance for early to mid-termone-shot herbicides.

In addition, acetolactate synthase (ALS) inhibitors have come to bewidely used in recent years, and weeds exhibiting resistance to ALSinhibitors have become a problem. There are few herbicides demonstratingadequate efficacy against ALS inhibitor-resistant biotypes of theperennials of Sagittaria trifolia and Sagittaria pygmeae. In addition,examples of perennial weeds that have caused problems in recent yearsinclude Eleocharis kuroguwai, Scirpus planiculmis and Scirpusnipponicus, while examples of annuals include Aeschynomene indica,Leptochloa chinensis and Murdannia keisak, and there are few herbicidesthat demonstrate adequate efficacy against these difficult-to-controlweeds.

On the other hand, numerous pyrazole derivatives are used practically asherbicides, and although pyrazole derivatives such as4-(2,4-dichlorobenzoyl)-1,3-dimethyl-5-pyrazolyl p-toluenesulfonate(common name: “Pyrazolate”),2-[4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazol-5-yloxy]acetophenone(common name: “Pyrazoxyfen”) or2-[4-(2,4-dichloro-m-toluoyl)-1,3-dimethylpyrazol-5-yloxy]-4′-methylacetophenone(common name: Benzofenap”) are widely used, their registered applicationrange for paddy weeds in Japan when used alone is up to the 1.5 leafstage, and although these pyrazole derivatives are effective against awide range of weeds, the efficacy thereof is not always adequate againstpaddy weeds of higher leaf stages.

In addition, although Compound 73 of Example 4 described in PatentDocument 1 in the form of1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-[methyl(prop-2-ynyl)amino]pyrazole-4-carbonitrile(common name: “Pyraclonil”) is effective against a wide range of weeds,its efficacy against paddy weeds of higher leaf stages is inadequate,and the registered application range in Japan against paddy weeds whenusing this herbicide alone is up to the 1.5 leaf stage.

CITATION LIST Patent Literature Document

Patent Document 1: WO 94/08999

Non-Patent Literature Document

Non-Patent Document 1: Suiden Zasso no Seitai to Sono Bojo—Suitosaku noZasso to Josozai Kaisetsu (Ecology of Paddy Weeds and theirControl—Explanation of Weeds of Rice Paddy Crops and Herbicide)”, p. 159

SUMMARY OF THE INVENTION Technical Problem

An object of the present invention is to provide a herbicide compositionthat has a wide herbicidal spectrum, is able to control worst weeds ofhigher leaf stages that present practical problems, and not causephytotoxicity to crops such as paddy rice.

Solution Problem

As a result of conducting extensive studies to achieve theaforementioned object, the inventors of the present invention found thata pyrazolylpyrazole derivative having a specific chemical structureexhibits a wide herbicidal spectrum over a long period of time,demonstrates superior herbicidal efficacy against worst weeds of higherleaf stages, and has adequate safety with respect to cultivated crops,thereby leading to completion of the present invention on the basis ofthese findings.

A compound represented by the following formula (I):

wherein,

R¹ represents a halogen atom,

R² represents a cyano group or nitro group,

R³ represents a C₂-C₄ alkyl group substituted with one or more halogenatoms or a C₁-C₂ alkoxy(C₁-C₃)alkyl group,

a represents 3 to 5, and

b represents 1 to 3.

In the present description,

a description in the manner of the previous “C_(a)-C_(b)” of eachsubstituent refers to the number of carbon atoms respectively present inthat group being from a to b.

Fluorine atoms, chlorine atoms, bromine atoms and iodine atoms areincluded in “halogen atoms”.

An “alkyl group” can be linear or branched, at least one of the hydrogenatoms contained in a substituent is substituted with a halogen atom, andalthough there are no limitations thereon, examples thereof includechloroethyl, dichloroethyl, trifluoroethyl, tetrafluoropropyl,bromoethyl, bromopropyl and cyclobutyl groups, and is each selectedwithin a range of the specified number of carbon atoms thereof.

An “alkoxy group” refers to an alkyl-O-group in which the alkyl moietyhas the above-mentioned meaning, and although there are no limitationsthereon, examples thereof include methoxy and ethoxy groups, and each isselected within a range of the specified number of carbon atoms thereof.

In the case where the aforementioned group or moiety is substituted witha plurality of halogen atoms, that group can be substituted with morethan one halogen atoms and/or substituents that are the same ordifferent.

In all of the formulas listed below, substituents and symbols have thesame meanings as defined for formula (I) unless specifically definedotherwise. The compound of formula (I) provided by the present inventioncan be easily synthesized by an alkylation reaction and a subsequentperfluoroamidation reaction of a compound represented by formula (II).

The compound of formula (II) can be synthesized fromtetrahydro-2H-pyran-2-ylideneacetonitrile or 5-chlorovaleryl chloride inaccordance with the methods described in WO 93/10100 and WO 94/08999.

The alkylation reaction of the compound of formula (II) can be carriedout with reference to known reaction conditions (see, for example, WO94/08999). This may also be carried out by a procedure consisting ofprotection of the amino group followed by alkylation and deprotectiondepending on the case.

The subsequent perfluoroamidation reaction can be easily carried outunder known reaction conditions and a known method described in theliterature cited therein (see, for example, Japanese Patent ApplicationLaid-open No. 2005-154420).

The compound of formula (I) provided by the present invention hassuperior herbicidal efficacy and is useful as a herbicide as is clearfrom the results of the herbicidal activity tests described in TestExamples 1 to 3 to be subsequently described.

The compound of formula (I) of the present invention has activityagainst numerous types of crop land weeds and non-crop weeds. Examplesof cultivated plants include gramineous plants such as rice, wheat,barley, corn, oats or sorghum, broadleaf crops such as soybeans, cotton,beets, sunflowers or rapeseed, fruit trees, vegetables such as fruitvegetables, root vegetables or leafy vegetables, and grasses, and thecompound of formula (I) can be used for the cultivation thereof.

The compound of the present invention has herbicidal efficacy againstthe various weeds listed below that cause problems in rice paddies inany of the treatment methods of soil treatment in an irrigated orunirrigated state, soil incorporation treatment and foliar treatment.Although the following lists examples thereof, these weeds are notlimited to the following examples.

Examples of paddy weeds that can be controlled by the compound offormula (I) of the present invention include Alismataceous weeds such asAlisma canaliculatum, Sagittaria trifolia or Sagittaria pygmaea,Cyperaceous weeds such as Cyperus difformis, Cyperus serotinus, Scirpusjuncoides, Eleocharis kuroguwai, Scirpus planiculmis or Scirpusnipponicus, Scrophulariaceous weeds such as Lindernia procumbens,Lindernia dubia subsp. dubia or Lindernia dubia, Pontederiaceous weedssuch as Monochoria vaginalis or Monochoria korsakowii, Potamogetonaceousweeds such as Potamogeton distinctus, Lythraceous weeds such as Rotalaindica or Ammannia multiflora, Asteraceous weeds such as Bidenstripartita or Bidens frondosa, Leguminoseous weeds such as Aeschynomeneindica, Commelinaceous weeds such as Murdannia keisak, and Gramineousweeds such as Echinochloa oryzicola, Echinochloa crus-galli var.crus-galli, Echinochloa crus-galli var. formosensis, Echinochloacrus-galli var. praticola, Echinochloa crus-galli var. caudata,Leptochloa chinensis, Leersia japonica, Paspalum distichum or Leersiaoryzoides.

In addition, the compound of the present invention has herbicidalefficacy against the various weeds listed below that cause problems infield land and non-crop land in any of the treatment methods of soiltreatment, soil incorporation treatment and foliar treatment. Althoughthe following lists examples thereof, these weeds are not limited to thefollowing examples.

Examples thereof include broadleaf weeds, including Solanaceous weedssuch as Solanum nigrum or Datura stramonium, Malvaceous weeds such asAbutilon avicennae or Sida spinosa, Convolvulaceous weeds such asIpomoea pupurea, Amaranthaceous weeds such as Amaranthus lividus,Asteraceous weeds such as Xanthium strumarium, Ambrosiaartemisiilifolia, Galinsoga ciliata, Cirsium arvense, Senecio vulgarisor Stenactis annuus, Brassicaceous weeds such as Rorippa indica, Sinapisarvensis or Capsella bursa-pastoris, Polygonaceous weeds such asPersicaria longiseta or Fallopia convolvulus, Portulacaceous weeds suchas Portulaca oleracea, Chenopodiaceous weeds such as Chenopodium album,Chenopodium ficifolium or Kochia scoparia, Caryophyllaceous weeds suchas Stellaria media, Scrophulariaceous weeds such as Veronica persica,Commelinaceous weeds such as Commelina communis, Lamiaceous weeds suchas Lamium amplexicaule or Lamium purpureum, Euphorbiaceous weeds such asEuphorbia supina or Euphorbia maculata, Rubiaceous weeds such as Galiumspurium, Galium spurium var. Echinospermon or Rubia argyi, Violaceousweeds such as Viola mandshurica, and Leguminoseous weeds such asSesbania exaltata or Cassia obfusitolia, and Gramineous weeds such asSorghum bicolor, Panicum dichotomiflorum, Sorghum halepense, Echinochloacrus-galli var. crus-galli, Digitaria ciliaris, Avena fatua, Eleusineindica, Setaria viridis, Alopecurus aequalis or Poa annua, andCyperaceous weeds such as Cyperus rotundus.

Moreover, the compound of the present invention is also able to controla wide range of weeds growing in mowed swaths, fallow land, orchards,grasslands, lawn grass plots, train line caps, vacant land and forestland, or on farm roads, causeways and other non-crop land.

Moreover, the compound of formula (I) of the present invention does notdemonstrate phytotoxicity that becomes a problem for paddy rice in thecase of any cultivation method such as direct seeding cultivation ortransplantation cultivation of paddy rice.

The compound of formula (I) of the present invention can be appliedbefore or after plant germination and can be mixed into soil beforeseeding.

Although the dosage of the compound of formula (I) of the presentinvention can be varied over a wide range corresponding to the type ofcompound, type of target plant, application window, location ofapplication, properties of desired effects and the like, and as ageneral reference thereof, the dosage can be within the range of about0.01 g to 100 g, and preferably about 0.1 g to 10 g, as the amount ofactive compound per are.

Although the compound of formula (I) of the present invention can beused alone, a formulation assistant and the like is normallyincorporated in the compound of formula (I) in accordance with ordinarymethods, and although there are no limitations thereon, it is preferablyformulated and used in any arbitrary drug form such as a dustablepowder, emulsifiable concentrate, oil miscible liquid, solubilizingagent, suspo-emulsion, fine granule, aerosol spray, less drifting dust,micro granule fine, fine grains F, granules, wettable powder, waterdispersible granules, flowable concentrate, throw-in types (Jumbo),tablets, paste, emulsion in oil, water soluble powder, water solublegranule, soluble concentration or capsule suspention.

There are no limitations on formulation assistants able to be used forformulation, and examples include solid vehicles, liquid vehicles,binders, thickeners, surfactants, anti-freezing agents andpreservatives.

Examples of solid vehicles include, but are not limited to, talc,bentonite, montmorillonite, clay, kaolin, calcium carbonate, sodiumcarbonate, sodium bicarbonate, mirabilite, zeolite, starch, acidic clay,diatomaceous earth, chaoite, vermiculite, slaked lime, vegetable powder,alumina, activated carbon, sugars, hollow glass, silica sand, ammoniumsulfate and urea.

Examples of liquid vehicles include, but are not limited to,hydrocarbons (such as kerosene or mineral oil), aromatic hydrocarbons(such as toluene, xylene, dimethyl naphthalene or phenyl xylyl ethane),chlorinated hydrocarbons (such as chloroform or carbon tetrachloride),ethers (such as dioxane or tetrahydrofuran), ketones (such as acetone,cyclohexanone or isophorone), esters (such as ethyl acetate, ethyleneglycol acetate or dibutyl maleate), alcohols (such as methanol,n-hexanol or ethylene glycol), polar solvents (such asN,N-dimethylformamide, dimethylsulfoxide or N-methylpyrrolidone) andwater.

Examples of binders and thickeners include, but are not limited to,dextrin, sodium salts of carboxymethyl cellulose, polycarboxylicacid-based polymer compounds, polyvinylpyrrolidone, polyvinyl alcohol,sodium lignin sulfonate, calcium lignin sulfonate, sodium polyacrylate,gum arabic, sodium alginate, mannitol, sorbitol, bentonite-based mineralmatter, polyacrylic acid and derivatives thereof, chaoite and naturalsugar derivatives (such as xanthan gum or guar gum).

Examples of surfactants include, but are not limited to, anionicsurfactants such as fatty acid salts, benzoates, alkylsulfosuccinates,dialkylsulfosuccinates, polycarboxylates, alkyl sulfate ester salts,alkyl sulfates, alkyl aryl sulfates, alkyl diglycol ether sulfates,alcohol sulfate ester salts, alkyl sulfonates, alkyl aryl sulfonates,aryl sulfonates, lignin sulfonates, alkyl diphenyl ether disulfonates,polystyrene sulfonates, alkyl phosphate ester salts, alkyl arylphosphates, styryl aryl phosphates, polyoxyethylene alkyl ether sulfateester salts, polyoxyethylene alkyl aryl ether sulfates, polyoxyethylenealkyl aryl ether sulfate ester salts, polyoxyethylene alkyl etherphosphates, polyoxyethylene alkyl aryl phosphate ester salts or salts ofnaphthalene sulfonate-formalin condensates, and nonionic surfactantssuch as sorbitan fatty acid esters, glycerin fatty acid esters, fattyacid polyglycerides, fatty acid alcohol polyglycol ethers, acetyleneglycol, acetylene alcohol, oxyalkylene block polymers, polyoxyethylenealkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene styrylaryl ethers, polyoxyethylene glycol alkyl ethers, polyoxyethylene fattyacid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethyleneglycerin fatty acid esters, polyoxyethylene hydrogenated castor oil orpolyoxypropylene fatty acid esters.

Examples of anti-freezing agents include, but are not limited to,ethylene glycol, diethylene glycol, propylene glycol and glycerin.

Examples of preservatives include, but are not limited to, benzoic acid,sodium benzoate, methyl paraoxybenzoate, butyl paraoxybenzoate,isopropyl methyl phenol, benzalkonium chloride, chlorhexidinehydrochloride, aqueous hydrogen peroxide, chlorhexidine gluconate,salicylic acid, sodium salicylate, zinc pyrithione, sorbic acid,potassium sorbate, dehydroacetic acid, sodium dehydroacetate,phenoxyethanol, isothiazoline derivatives such as5-chloro-2-methyl-4-isothiazolin-3-one or 2-methyl-4-isothiazolin-3-one,2-bromo-2-nitropropane-1,3-diol and salicylic acid derivatives.

The previously mentioned solid vehicles, liquid vehicles, binders,thickeners, surfactants, anti-freezing agents and preservatives can eachbe used alone or in a suitable combination thereof corresponding to thepurpose of use and the like.

Although the incorporated ratio of the compound of formula (I) of thepresent invention with respect to the total herbicide composition of thepresent invention can be increased or decreased as necessary and thereare no particular limitations thereon, it is normally about 0.01% byweight to 90% by weight, and for example, in the case of being in theform of a dustable powder or granules, is preferably about 0.1% byweight to 50% by weight and more preferably about 0.5% by weight to 10%by weight, while in the case of being in the form of an emulsifiableconcentrate, wettable powder or water dispersible granules, ispreferably about 0.1% by weight to 90% by weight and more preferablyabout 0.5% by weight to 50% by weight.

These preparations can be provided for use in various types ofapplications by diluting to a suitable concentration as necessaryfollowed by spraying or applying directly to plant foliage, soil or thesurface of a rice paddy and the like.

The following provides an explanation of the present invention throughexamples thereof.

EXAMPLES Example 1 Method for the synthesis ofN-(2-chloroethyl)-N-(1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-4-cyanopyrazol-5-yl)-2,2,2-trifluoroacetamide(Compound 1)

Formic acid (18.4 g) was slowly dropped into acetic anhydride (33.7 g)cooled to 5° C. followed by stirring for 2 hours at 60° C. (ReactionMixture A). Separate from the above,5-amino-1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)pyrazole-4-carbonitrile(26.3 g) was dissolved in acetonitrile (200 ml) and stirred. Thepreviously prepared Reaction Mixture A was slowly dropped therein andreacted for 1 day at room temperature and then for 4 hours at 60° C.Subsequently, the solvent was distilled off under reduced pressurefollowed by neutralizing using aqueous potassium carbonate solution,washing the precipitated solid with water and drying to obtainN-(1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-4-cyanopyrazol-5-yl)formamide(28 g).

N-(1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-4-cyanopyrazol-5-yl)formamide(4.4 g) was dissolved in N,N-dimethylformamide (15 ml) followed by theaddition of potassium carbonate (2.5 g) and stirring.1-bromo-2-chloroethane (2.6 g) was slowly dropped therein and reactedfor 6 hours at 50° C., and following completion of the reaction, waterwas added to the reaction mixture followed by extraction with ethylacetate. After drying with sodium sulfate, the solvent was concentratedunder reduced pressure to obtain a crude product (5.2 g).

The resulting crude product (5.2 g) was dissolved in ethanol (20 ml)followed by the addition of 10% hydrochloric acid (5.5 g) and stirringfor 3 hours at 65° C. Following completion of the reaction, water wasadded to the reaction mixture and the precipitated solid was filteredout and dried to obtain1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-(2-chloroethylamino)pyrazole-4-carbonitrile(4.5 g).1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-(2-chloroethylamino)pyrazole-4-carbonitrile(1.0 g) was dissolved in acetonitrile (6 ml) and stirred followed byslowly dropping therein trifluoroacetic anhydride (3.2 g). The reactionmixture was stirred for 4 days at 40° C. followed by the addition ofsaturated aqueous sodium hydrogen carbonate solution to the reactionliquid and extracting with ethyl acetate. After drying with sodiumsulfate, the solvent was distilled off under reduced pressure and theresulting crude product was purified by silica gel column chromatography(hexane/ethyl acetate=1:1) to obtain the desired compound (0.9 g).

Example 2 Method for the synthesis ofN-(1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-4-cyanopyrazol-5-yl)-N-(2-methoxyethyl)-2,2,2-trifluoroacetamide(Compound 2)

5-amino-1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)pyrazole-4-carbonitrile(43.1 g) was dissolved in N,N-dimethylformamide (170 ml) followed by theaddition of 55% sodium hydride (8.6 g) and stirring. After confirmingthat foaming had subsided, 2-bromoethyl methyl ether (25 g) was slowlydropped in while cooling the reaction mixture with an ice bath followedby reacting for 8 hours at 60° C. following completion of dropping.Following completion of the reaction, water was added to the reactionmixture and the precipitated solid was washed with ethyl acetate toobtain

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-(2-methoxyethylamino)pyrazole-4-carbonitrile(36 g)

Acetonitrile (65 ml) was added to the resulting1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-(2-methoxyethylamino)pyrazole-4-carbonitrile (20 g) followed by slowly droppingtherein trifluoroacetic anhydride (14.4 g). The reaction mixture wasstirred for 10 hours at 50° C. followed by adding saturated aqueoussodium hydrogen carbonate solution to the reaction mixture andextracting with ethyl acetate. After drying with sodium sulfate, thesolvent was concentrated under reduced pressure and the resulting crudeproduct was purified by recrystallization (ethyl acetate/hexane) toobtain the desired compound (22.7 g).

The starting material in the form of the compound of formula (II) wassynthesized in accordance with WO 93/10100 and WO 94/08999.

The examples listed in the following tables can be synthesized by thesame manner as the above-mentioned methods or obtained in the samemanner as the above-mentioned methods.

TABLE 1 (I)

Com- Refractive pound R¹ R² R³ b a mp index (° C.) 1 Cl CN 2-chloroethyl1 4 87-89 2 Cl CN 2-methoxyethyl 1 4 102-103 3 Cl CN 3-chloropropyl 1 4123-124 4 Cl CN 3,3,3-trifluoropropyl 1 4 94-95 5 Cl CN 2-ethoxyethyl 14 1.5074(26.2) 6 Cl CN 3-methoxypropyl 1 4 1.5086(26.9) 7 Cl CN3,3,3-trifluoropropyl 2 4 1.4816(25.3) 8 Cl CN 2,2,2-trifluoroethyl 1 4100 9 Cl CN 2-methoxyethyl 1 3 10 Cl CN 2-methoxyethyl 1 5 11 Cl CN2-chloroethyl 1 3 12 Cl CN 2-chloroethyl 1 5 13 Br CN 2-methoxyethyl 1 4120 14 Br CN 2-ethoxyethyl 1 4 68-69 15 Br CN 3-methoxypropyl 1 4 97-9816 Br CN 2-chloroethyl 1 4 108-109 17 Br CN 3-chloropropyl 1 4 109-11018 Br CN 3,3,3-trifluoropropyl 1 4 98-99 19 Br CN 4-chlorobutyl 1 486-87 20 Cl NO₂ 2-methoxyethyl 1 4 21 Cl NO₂ 2-ethoxyethyl 1 4 82-83 22Cl NO₂ 3-chloropropyl 1 4 132-133 23 Br NO₂ 2-methoxyethyl 1 4 82-83

Preparation Examples

1. Dustable powder Compound of formula (I) 10 parts by weight Talc 90parts by weight

A dustable powder is obtained by mixing the above components and finelycrushing with a hammer mill.

2. Wettable Powder Compound of formula (I)   10 parts by weightPolyoxyethylene alkyl aryl ether sulfate 22.5 parts by weight Whitecarbon 67.5 parts by weight

A wettable powder is obtained by mixing the above components and finelycrushing the mixture with a hammer mill.

3. Flowable concentrate Compound of formula (I) 10 parts by weightPolyoxyethylene alkyl ether phosphate 10 parts by weight Bentonite  5parts by weight Ethylene glycol  5 parts by weight Water 70 parts byweight

A flowable concentrate is obtained by mixing the above components andcrushing using a wet pulverizer.

4. Emulsifiable concentrate Compound of formula (I) 15 parts by weightEthoxylated nonylphenol 10 parts by weight Cyclohexanone 75 parts byweight

An emulsifiable concentrate is obtained by mixing the above components.

5. Granules Compound of formula (I)  5 parts by weight Calcium ligninsulfonate  3 parts by weight Polycarboxylate  3 parts by weight Calciumcarbonate 89 parts by weight

The above components are mixed followed by adding water, kneading,extruding and granulating. Subsequently, granules are obtained by dryingfollowed by sizing.

Biological Testing Examples 1. Paddy Herbicidal Activity Test

Rice paddy soil was filled into a 1/10000 are pot followed by theaddition of suitable amounts of water and chemical fertilizer, kneading,seeding with Echinochloa crus-galli, Monochoria vaginalis and Scirpusjuncoides and maintaining in an irrigated state at a water depth of 3cm.

Wettable powder of Target Compound (I) shown in Table 1 prepared incompliance with the preparation examples were diluted with a suitableamount of water, rice plants in the 2.0 leaf stage were transplantedduring 3.5 leaf stage of Echinochloa crus-galli, and treated by droppingin chemical in the prescribed amount per are using a pipette.

After treating for 30 days in a glass greenhouse at an averageatmospheric temperature of 30° C., the herbicidal efficacy thereof wasinvestigated.

Evaluation of herbicidal efficacy was carried out by comparing growthinhibition rate (%) with an untreated group, while evaluation ofphytotoxicity was carried out by comparing growth inhibition rate (%)with the state of a complete eradication group, and were evaluated at 11levels indicated below.

0 (exponent): 0% to less than 10% (growth inhibition rate)

1: 10% to less than 20%

2: 20% to less than 30%

3: 30% to less than 40%

4: 40% to less than 50%

5: 50% to less than 60%

6: 60% to less than 70%

7: 70% to less than 80%

8: 80% to less than 90%

9: 90% to less than 100%

10: 100%

The results are shown in Table 2.

Control agent 4.63 (described in WO 94/08999)

Control agent 4.92 (described in WO 94/08999)

Control agent 4.185 (described in WO 94/08999)

Control agent 4.237 (described in WO 94/08999)

Control agent 4.238 (described in WO 94/08999)

TABLE 2 5g^(a.i.)/10a 1g^(a.i.)/10a Echinochloa Monochoria Scirpus RiceEchinochloa Monochoria Scirpus Rice Compound crus-galli vaginalisjuncoides plants crus-galli vaginalis juncoides plants 1 10 9 10 1 9 8 90 2 9 9 9 1 9 8 9 0 3 9 8 8 1 8 7 8 1 4 10 8 9 0 9 8 9 0 5 9 8 9 1 9 8 80 6 10 9 8 0 9 8 7 0 7 9 9 8 0 9 7 8 0 8 9 9 10 0 8 9 9 0 13 9 9 8 1 9 87 0 14 9 8 9 1 9 7 8 1 15 10 8 9 1 9 8 8 0 16 10 8 9 1 9 7 8 0 17 8 9 80 8 9 7 0 18 10 8 9 1 9 7 9 0 20 10 9 10 1 9 9 9 1 23 8 8 8 0 7 8 8 04.63 3 2 2 1 2 1 1 0 4.92 2 1 4 1 1 0 2 0 4.185 4 0 6 2 2 0 5 2 4.237 43 4 2 1 2 2 1 4.238 4 1 3 2 2 0 2 2

2. Farming Soil Treatment Test

Field soil was filled into a 1/6000 are pot followed by seeding withDigitaria ciliaris, Chenopodium album and Amaranthus retroflexus andcovering with soil.

Wettable powder of compounds of formula (D shown in Table 1 prepared incompliance with the preparation examples were diluted with water to theprescribed amount of chemical and uniformly sprayed onto each soilsurface layer using 10 liters of sprayed water per are prior to weedgrowth following seeding.

After treating for 30 days in a glass greenhouse at an averageatmospheric temperature of 30° C., the herbicidal efficacy thereof wasinvestigated.

Evaluation of herbicidal efficacy was carried out in the same manner asthe above-mentioned Test Example 1.

The results are shown in Table 3.

TABLE 3 10g^(a.i.)/10a 5g^(a.i.)/10a Chenopodium Amaranthus ChenopodiumAmaranthus Compound Digitaria ciliaris album retroflexus Digitariaciliaris album retroflexus 1 10 10 10 10 10 10 2 10 10 10 10 10 10 16 1010 10 10 10 10 20 10 10 10 10 10 10 4.63 3 5 5 3 4 4 4.92 3 5 4 2 4 34.185 5 5 6 3 4 5 4.237 5 4 5 4 4 5 4.238 6 5 5 5 4 4

3. Weed Foliar Treatment Test

Soil was filled into a 1/6000 are pot followed by seeding with Digitariaciliaris, Chenopodium album and Amaranthus retroflexus, covering withsoil, and cultivating in a glass greenhouse at an average atmospherictemperature of 25° C.

Wettable powder of Target Compound (I) shown in Table 1 prepared incompliance with the preparation examples were diluted with water to theprescribed amount of chemical and uniformly sprayed onto the weeds using15 liters of sprayed water per are when Digitaria ciliaris had grown tothe 1.0 to 2.0 leaf stage.

After treating for 3 weeks in a glass greenhouse at an averageatmospheric temperature of 25° C., the herbicidal efficacy thereof wasinvestigated.

Evaluation of herbicidal efficacy was carried out in the same manner asthe above-mentioned Test Example 1.

The results are shown in Table 4.

TABLE 4 10g^(a.i.)/10a 5g^(a.i.)/10a Chenopodium Amaranthus ChenopodiumAmaranthus Compound Digitaria ciliaris album retroflexus Digitariaciliaris album retroflexus 1 10 10 10 10 10 10 2 10 10 10 10 10 10 16 1010 10 10 10 10 20 10 10 10 10 10 10 4.63 4 5 6 2 3 3 4.92 5 6 5 4 3 44.185 6 6 6 4 5 6 4.237 6 5 6 5 4 4 4.238 5 6 6 4 4 5

INDUSTRIAL APPLICABILITY

According to the present invention, the compound for formula (I) of thepresent invention is useful as a herbicide against harmful plants sinceit has superior herbicidal efficacy against undesirable plants.

1. A compound represented by the following formula (I):

wherein, R¹ represents a halogen atom, R² represents a cyano group ornitro group, R³ represents a C₂-C₄ alkyl group substituted with one ormore halogen atoms or a C₁-C₂ alkoxy-C₁-C₃-alkyl group, a represents 3to 5, and b represents 1 to
 3. 2. A herbicide composition containing aherbicidally effective amount of at least one type of the compoundaccording to claim
 1. 3. The herbicide composition according to claim 2,further containing a formulation assistant.
 4. A method for controlundesirable plants, comprising the step of applying an effective amountof at least one type of the compound according to claim 1 to anundesirable plant or the location of the undesirable vegetation.
 5. Ause of the compound according to claim 1 for control undesirable plants.6. The use according to claim 5, wherein the compound is used forcontrol undesirable plants among useful agricultural crops.
 7. A methodfor control undesirable plants, comprising the step of applying aneffective amount of the herbicide composition according to claim 2 to anundesirable plant or the location of the undesirable vegetation.
 8. Amethod for control undesirable plants, comprising the step of applyingan effective amount of the herbicide composition according to claim 3 toan undesirable plant or the location of the undesirable vegetation.